1. Field
Embodiments relate generally to fabrication of semiconductor devices, and more particularly to a method of fabricating a transistor structure in which a gate dielectric layer surrounds a channel on more than one side thereof.
2. Background
A variety of multiple-gate transistors have been proposed. For example, FIG. 10 shows a tri-gate structure 200, in which a gate dielectric layer (e.g., oxide layer) 220 surrounds a channel 250 on three sides, yielding control of two vertical surface regions and horizontal layer region of the channel adjacent to the gate dielectric layer 220. In certain cases, multiple-gate transistors may be desirable since transistor performance can be improved by increasing an amount of area that gate dielectric layer is in contact with a channel of a transistor structure.
In the field of semiconductor device fabrication, replacement gate processes may be used for constructing transistors with a wide selection of gate materials. In a replacement gate flow process, an entire transistor may be fabricated with a sacrificial gate electrode and a sacrificial gate dielectric. After all of the high temperature fabrication processes have taken place, the sacrificial gate electrode and the sacrificial gate dielectric may be removed and a desired gate material, such as metal gate electrode, may be deposited.